Air sampling is used to collect samples of airborne particles that are present in an environment. Analyses of the air samples can provide information concerning potential exposure to harmful respirable agents. Bioaerosol sampling can be used to identify particles of biological origin, such as, viable and non-viable fungal spores, bacteria, pollen, skin cells, fibers and insect parts.
Until recently, analyses of bioaerosol samples typically involved directly counting the organisms in a sample or indirectly by providing culture media in an environment and counting colony-forming units. While these methods provide reasonably adequate assessment of bioaerosol concentration, such methods are time consuming (e.g., some analyses may take days or even weeks to complete) and may be unreliable. Recently, the threat of biological warfare and terrorist attack has prompted the development of highly sensitive molecular techniques for detecting microorganisms, such as polymerase chain reaction (PCR) and immunological assays.
Sampling devices that are currently used for collecting bioaerosols for subsequent analysis include filters, impingers, and impactors. However, such devices suffer from disadvantages that limit their use in assessing exposure to airborne bioparticulates. For example, samples extracted from filters are often insufficient for determining the concentration of bioparticulates in the air because of poor extraction efficiency. Impingers and impactors may be suitable for short-term samplings; however, these devices cannot be used for long-term exposure assessment because of liquid evaporation in impingers and potential particle re-entrainment in impactors.
Hence, there is a need for new and improved devices for sampling airborne particles, and especially for sampling devices that can monitor ambient air for the presence of biowarfare pathogens, such as anthrax spores, potentially pathogenic mold in the environment, and other potentially hazardous bioparticulates.